Three teenage girls are believed to be behind the defacing of a historic monument and a number of walls around Leighton town centre.
The teens were allegedly spotted daubing the medieval Market Cross with spray paint at 3pm on Sunday, before moving on to Lloyds Bank and down Market Square.
A woman who was having lunch at The Swan Hotel at the time took pictures of the alleged culprits in the act, before warning them to stop.
The woman, who wished to remain anonymous, told the LBO: “We went out for a bit of air and saw them spraying the memorial and when they realised I was taking pictures they started mouthing off.
“I told them that I would let the police know but didn’t approach them as I was with my child.
“It’s not very nice, I don’t want my seven-year-old to think that it’s OK to do that.”
She added: “The problem is that on a Sunday there are not any police officers around or as many people to stop them or speak to them.
“In Leighton Buzzard we don’t have many shops open on a Sunday so people don’t come into the town centre.
“We have reported it to the police and hopefully they will get a good telling off.”
Although for legal reasons the LBO cannot show the faces of the alleged vandals, the photos have been passed to Beds Police which says it is investigating the reports.
Anyone with information is asked to call 101 and quote JD/14566/2016.